Fertilizers via the Middle Corridor: how urea and sulphur from Central Asia reach Poti and Batumi while the Strait of Hormuz is closed — lots of 5,000–100,000 tonnes, hoppers, big bags, dangerous-goods classes and CBAM

Fertilizer is the least glamorous cargo on the Middle Corridor and, in 2026, one of the most important. When military escalation around Iran closed the Strait of Hormuz to commercial traffic in late February, it did not only stop oil and gas. It stopped roughly a quarter of the world's nitrogen fertilizer exports and about a third of its traded urea, because Qatar, Saudi Arabia, Iran, the UAE, Oman and Bahrain all ship their product through the same forty-kilometre channel. By the WTO's tracking, fertilizer shipments through the strait fell to near zero in early March and were still there in July. Urea went from around $400 a tonne to $850 in April — an 80% rise in two months and the highest level since April 2022 — before easing to about $453 in June. Sulphur, the feedstock for phosphate fertilizer, doubled in price.

Every tonne that disappeared from the Gulf has to come from somewhere else, and the somewhere else is unusually close to Georgia. Turkmenistan, Uzbekistan, Kazakhstan and Azerbaijan together produce several million tonnes a year of exactly the products the market lost — urea, ammonium nitrate, ammonia and sulphur — and their only route to a deep-sea buyer that avoids both the Gulf and Russia runs by rail across the Caspian to the Black Sea. This article is about that route as it physically works: which plants, which wagons, what the Batumi terminal can and cannot do, why the same corridor that was 'too expensive for bulk' a year ago is now full, how the EU's carbon border mechanism changes the paperwork from 2026, and where the real limits are.

What the Hormuz shutdown did to fertilizer trade in 2026

Two of these numbers matter more than the rest for anyone planning a shipment. The first is the 24.8% share: the Gulf is not the whole nitrogen market, so the world did not run out of urea — it lost its cheapest and most convenient source, and every alternative supplier and route was repriced upward. The second is the timeline: near-zero traffic for at least five months, with the World Bank expecting urea to end 2026 roughly 60% higher on average than 2025 and to ease only in 2027. That is not a spike to wait out; it is a season, which is exactly the horizon on which a producer commits volume to a new corridor.

Central Asia and the Caucasus as the alternative supply base

The alternative supply base has been in place for years; what changed is who needs it. Turkmenistan runs three urea plants — Tejenkarbamid, Marykarbamid and, since 2018, Garabogazkarbamid on the Caspian coast, with a design capacity of 1.155 million tonnes of urea and 660,000 tonnes of ammonia a year. Garabogazkarbamid produced about 994,000 tonnes in the first eleven months of 2024 and exported around a million, and a further urea complex in the Balkan region begins construction in 2026 for commissioning in 2030. Uzbekistan's Navoiyazot and Ferganaazot make urea and ammonium nitrate for export; the Uztemiryulcontainer block train that carried 39 forty-foot containers of urea from Tashkent to Bulgaria, Greece and Italy in 25–30 days is the proof that the container version of the route works. Azerbaijan's Sumgait urea plant sits directly on the corridor's rail line. Georgia has its own producer, Rustavi Azot, with capacity of up to 500,000 tonnes of ammonium nitrate a year, exporting through Poti.

Kazakhstan is the sulphur story. The country produces about 4 million tonnes a year — roughly 5% of world output — almost all of it recovered from sour gas at Tengiz and Kashagan, with Tengizchevroil's granulation plant alone turning out 40,000 tonnes a month. Historically about 3.5 million tonnes a year of exports moved by rail across Russia to Ust-Luga on the Baltic; 2.3 million tonnes transited the Russian network in the first half of 2025 alone. On 24 May 2026 Russia's federal rail agency banned the carriage of Kazakh sulphur to Russian sea ports and border crossings indefinitely. In the same spring that Gulf sulphur vanished from the market, Kazakhstan's traditional export route to the sea closed. The Caspian–Georgia route is now not one option among several for that sulphur; for seaborne buyers it is the option.

Batumi's fertilizer terminal: the infrastructure that already exists

The reason this flow can be switched on rather than invented is a single facility in Batumi. The Batumi Fertilizer Terminal, financed by the trader Trammo with its Georgian partner Wondernet Express, opened on 16 June 2021 specifically for urea and sulphur arriving by rail from Turkmenistan, Uzbekistan, Kazakhstan and Azerbaijan. Its capacity is above 1.5 million tonnes a year. It has three enclosed warehouses holding 80,000 tonnes — enough to accumulate a full vessel lot under roof, which matters because urea cakes and sulphur dust in the open — and ship loaders rated at 1,200 tonnes an hour, so a 50,000-tonne cargo is on board in under three days. When it opened it was already holding 25,000 tonnes of Turkmen urea; the corridor did not wait for the Hormuz crisis to exist.

Poti plays the other role. Its general-cargo berths handle bagged and big-bagged fertilizer, the Poti New Sea Port project is reconstructing a berth and buying bulk-handling equipment primarily for fertilizer, and the container terminal is where the Uzbek urea train was transhipped. Georgian ammonium nitrate from Rustavi leaves through Poti, and the port is now a recognised enough origin that a price-reporting agency publishes an FOB Poti ammonium nitrate assessment. Between the two ports, Georgia's coast can take fertilizer in every commercial form: bulk urea and sulphur at Batumi, bags and containers at Poti.

Why bulk fertilizer 'did not suit' the Middle Corridor — and what changed

Readers of our earlier piece on what actually moves on the Middle Corridor will remember the blunt line that low-value bulk — grain, fertilizer, base metals — does not suit the route and is cheaper by sea. In normal years that was simply true: a tonne of urea from the Gulf reached India, Brazil or Europe on a Supramax at a fraction of the cost of rail plus a ferry plus a second port. Six things changed at once in 2026.

• The cheap sea route stopped existing — with Hormuz closed, Gulf urea and sulphur are not competing with the corridor on price; they are absent, and the comparison is now between Central Asian product by rail and no product at all
• The price of the cargo doubled — at $850 rather than $400 a tonne, the same freight bill is half the share of the delivered price it used to be, which is exactly the arithmetic that makes 'low-value bulk' suddenly worth moving overland
• Russia closed the northern exit for Kazakh sulphur — the 24 May 2026 rail ban removed the route that carried 2.3 million tonnes in a half-year, so the Caspian is not a choice but a necessity for that volume
• The terminal was already built — Batumi's 1.5-million-tonne fertilizer terminal with 80,000 tonnes of covered storage means the corridor did not have to improvise bulk handling, which is what usually kills a new bulk flow
• Buyers redrew their supplier lists — importers that took two-thirds of their nitrogen from the Gulf, as India did, went looking for any origin with a sea outlet; Turkish, Mediterranean and African buyers found one on the Black Sea
• Public money followed the traffic — in April 2026 the World Bank committed $3.3 billion to the corridor, including $1.9 billion for the Istanbul North rail crossing and $1.4 billion for the Karagandy–Zhezkazgan highway, and Türkiye's vice-president called the Middle Corridor 'a mandatory choice'

None of this repeals the underlying economics. When the strait reopens and Gulf urea is back at $400, most of this bulk will return to the sea, and the corridor will keep the flows that have structural reasons to stay: Kazakh sulphur while the Russian ban holds, Turkmen urea for which Batumi was built, containerised lots to buyers who value 25–30-day transit over the cheapest possible ton-mile. The point of moving now is to have the wagons, the terminal slots and the buyer relationships in place for that longer tail.

How a fertilizer lot moves: from the plant to a Black Sea vessel

The chain looks simple on a map and is decided by one choice made at the plant gate: the format. Fertilizer loaded into a mineral hopper is bulk cargo for the rest of the journey — it can be tipped into a covered warehouse and conveyed onto a ship at Batumi, but it cannot be turned into containers at the quay without a full transload through a bagging line. Fertilizer stuffed into 20-foot boxes at Navoi or Tashkent is container cargo for the rest of the journey — it rides block trains, crosses the Caspian on the same ferries, is lifted at Poti and goes on a feeder, and it never sees the Batumi terminal. Both are correct; mixing them mid-route is what produces the horror stories.

The Caspian is the same constraint for fertilizer as for every other cargo on the corridor, with one advantage: hoppers and covered wagons roll onto rail ferries, so bulk does not have to be reloaded at Aktau, Kuryk or Turkmenbashi. The crossing itself takes 17–24 hours; the wait for a ferry slot, with departures roughly every 3–5 days and no fixed timetable, is what stretches a 12-day rail plan into 18. For a 50,000-tonne vessel lot that is about 700 hopper wagons, which no single ferry carries, so accumulation happens on the Georgian side — which is precisely why 80,000 tonnes of covered storage at Batumi is the number that makes the whole scheme work.

Bulk, big bags or containers: choosing the format

Choosing between these formats is a commercial decision before it is a logistics one, and it is worth making explicitly rather than inheriting whatever the plant did last year. Bulk is cheapest per tonne only where a bulk terminal exists at both ends; for a buyer in a small Mediterranean port without one, containers or bagged break-bulk from Poti can be cheaper delivered even if the rail leg costs more. The corridor's own transit-time advantage — 25–30 days to an Italian or Greek port against far longer via the Cape while Suez and Hormuz are both disrupted — is largest for containerised lots, because they skip the accumulation wait at the terminal.

Dangerous-goods classes, moisture and contamination

Urea is not classified as dangerous goods, which is why it is the easiest fertilizer to move and store. Its enemies are water and heat: it is hygroscopic, cakes into blocks above roughly 60% relative humidity, and loses nitrogen if it gets hot and wet, so covered wagons, sealed hoppers, enclosed storage and dry holds are not refinements but the difference between granules and a solid mass at discharge. Sulphur, formed as granules or pastilles, is a class 4.1 flammable solid under ADR, RID and the IMDG Code and falls under the IMSBC Code when carried in bulk; its practical problems are dust, which is an explosion and health hazard in enclosed spaces, and corrosion, because wet sulphur forms sulphuric acid that attacks wagon floors and ship holds unless surfaces are lime-washed and cargo is kept dry.

Ammonium nitrate is the one that requires a dangerous-goods file in every mode: fertilizer-grade AN is UN 1942 and AN-based fertilizers are UN 2067, both class 5.1 oxidisers, with segregation from fuels, sulphur, organic material and reducing agents, quantity limits at the port and mandatory declarations, packaging codes and emergency information on the transport documents. Contamination between products is the other rule that is easy to state and easy to break: a hopper that carried sulphur must be cleaned before urea, and AN must never share a hold, a wagon or a warehouse bay with sulphur — a mixed pile is a fire that starts itself. The Batumi terminal's decision to handle only urea and sulphur, in separate warehouses, is a segregation policy as much as a commercial one.

CBAM: what an EU importer of urea or ammonium nitrate must do from 2026

Fertilisers are one of the six product groups covered by the EU's Carbon Border Adjustment Mechanism, and the definitive regime started on 1 January 2026. That has consequences that reach back down the corridor to the producer, because an importer cannot declare embedded emissions it does not know.

• Only the goods are covered, not the freight — CBAM prices the embedded emissions of ammonia, nitric acid, urea, ammonium nitrate and mixed fertilizers themselves; the route the cargo takes changes nothing, as we explained in the article on compliance and route choice
• The EU importer must be an authorised CBAM declarant — from 2026 only authorised declarants may import CBAM goods above the threshold; applications go through the national competent authority
• The 50-tonne de minimis — importers whose cumulative net mass of CBAM goods in cement, steel, fertilisers and aluminium stays below 50 tonnes in a calendar year are exempt; one 20-foot container of urea already exceeds it
• Annual declaration and certificates — 2026 imports are declared by 30 September 2027, verified emissions included, and CBAM certificates covering them are purchased from 2027 and surrendered against the declaration
• Producer data decides the bill — if the plant cannot provide verified actual emissions, default values apply, and for nitrogen fertilizers made with gas-based ammonia the default is rarely favourable; Rustavi Azot has already redirected part of its exports away from the EU for this reason
• Non-EU buyers are unaffected — Türkiye, North Africa, Brazil and India impose no carbon charge at the border today, which is one reason Black Sea fertilizer flows out of Georgia currently lean towards those markets

For a shipment planned now, the practical sequence is: confirm whether the consignee is in the EU; if so, confirm they hold or have applied for declarant status; obtain the producer's emissions data or agree who carries the default-value cost; and only then fix the route. Doing it in the other order produces cargo sitting in Poti with a buyer who cannot clear it.

Lot sizes, vessel classes and the Black Sea leg

Fertilizer trades in lots that start at a few thousand tonnes and routinely reach 50,000–100,000 tonnes for a single contract, and the corridor has to be sized to that. A 5,000-tonne bagged lot moves comfortably as break-bulk or containers through Poti. A 30,000–50,000-tonne bulk lot is a Handysize or small Supramax at Batumi, accumulated under roof over two to four weeks of rail arrivals and loaded in under three days. A 100,000-tonne contract is several vessels over a season and needs a wagon plan agreed with the railways in advance, because 100,000 tonnes is roughly 1,400 hopper loads and Kazakh, Turkmen and Georgian wagon fleets are finite. Draft is the other ceiling: Georgia's Black Sea ports take Handysize and Supramax tonnage, not the Capesize lots the Gulf loads, so a large buyer receives its volume in more, smaller parcels.

From the quay the geography is favourable. Türkiye, the largest fertilizer importer within reach, is a day's sailing away; Constanța, Burgas, Piraeus and the Italian ports are inside a week; North Africa and Brazil are reachable with the Turkish Straits transit and, for now, without the Suez and Bab al-Mandeb exposure that Gulf cargo cannot avoid. War-risk premiums on the Black Sea move with the headlines and should be priced per voyage rather than assumed.

Development prospects

The near-term capacity picture is being expanded on every leg at once. Turkmenistan's new urea complex in the Balkan region starts construction in 2026 for commissioning in 2030, adding to Garabogazkarbamid's 1.155 million tonnes. Kazakhstan's Kuryk and Aktau are the corridor's Caspian gate for wagons, and the World Bank's April 2026 package of $3.3 billion targets the two bottlenecks bulk feels most: the Karagandy–Zhezkazgan highway in Kazakhstan and the Istanbul North rail crossing in Türkiye. In Georgia, Poti's bulk berth reconstruction is aimed at fertilizer, the new harbour crane lifts general-cargo handling by around 500,000 tonnes by the end of 2026, and Anaklia's first phase from 2029 gives the coast a deep-water port able to load larger bulk carriers than Batumi or Poti can today.

The demand side is set for at least a season: the World Bank projects urea prices about 60% higher across 2026 and the overall fertilizer index up more than 30%, easing in 2027 — and even after the strait reopens, Kazakh sulphur has no Russian exit while the May 2026 ban stands. The realistic prospect is not that the Middle Corridor replaces the Gulf as the world's fertilizer highway; it is that the Batumi–Poti route keeps a permanent share of Central Asian nitrogen and sulphur that it never had before 2026, on infrastructure that is already paid for.

In short

The Hormuz shutdown turned a cargo that the Middle Corridor was 'wrong for' into one it is carrying at scale: a quarter of the world's nitrogen exports lost their route, urea doubled in price, Russia closed the exit for Kazakh sulphur, and Georgia already had a 1.5-million-tonne fertilizer terminal on the Black Sea. The rules for doing it well are the same as for any bulk chemical — choose bulk, bags or containers at the plant gate and keep to it; treat sulphur as class 4.1 and ammonium nitrate as class 5.1 with real segregation; keep urea dry; settle the CBAM question before the cargo moves if the buyer is in the EU; and size the wagon plan to the contract, not the first vessel. Tell us the product, the plant and the tonnage, and we will lay out the route from the railhead to the Black Sea as it works this season.

See also: Port of Batumi · Port of Poti · Dangerous goods: classes and documents · Railway wagon types · Compliance and route choice · Kazakhstan copper exports via the Middle Corridor